Genetic Epidemiology of Type 2 Diabetes in the Urhobo Ethnic Group: A Family History and Candidate Gene Study in Delta State

Type 2 diabetes mellitus (T2DM) has a strong heritable component, with risk substantially elevated in individuals with a first-degree relative with the condition. The Urhobo ethnic group in Delta State, South South Nigeria, has experienced rising rates of T2DM in recent decades, yet ethnic-specific genetic risk data remain largely unavailable. This study investigated family history patterns and the association of selected candidate gene polymorphisms with T2DM in the Urhobo population. A case-control study design enrolled 150 T2DM patients and 150 non-diabetic controls of Urhobo ethnicity from the Central Hospital Warri and associated clinics. Family history of diabetes was documented across three generations. Genomic DNA was extracted and genotyped for the TCF7L2 rs7903146 polymorphism, the most robustly replicated T2DM susceptibility locus globally. Chi-square tests and logistic regression adjusted for body mass index, age, and physical activity were applied. A significant association between positive family history and T2DM was confirmed. The TCF7L2 risk allele demonstrated a moderate association with disease status in this Urhobo cohort, warranting expanded multi-locus studies. Keywords: type 2 diabetes, TCF7L2, Urhobo, Delta State, candidate gene